A System Identification Method Based on Host Computer and Programmable Controller

Abstract

The invention discloses a system identification method based on an upper computer and a programmable logic controller. According to the system identification method, stimulus signal-pseudorandom multidigit signals PRMS used for identification are generated by programming on the programmable logic controller; the characteristics of the upper computer WinCC and the lower computer programmable logic controller are fully used for collecting input and output data at a high speed (the collection cycle can reach 5 ms), and in this way it is guaranteed that sufficient data can be used for system identification. In order to achieve high-speed data collection of the WinCC, the signal data continuously collected are sequentially stored in data blocks on the programmable logic controller, a plurality of external variables corresponding to all process variables in the data blocks are set up in the upper computer WinCC, and the high-speed data collection of the WinCC is indirectly achieved in the mode that the multiple variables read continuous values of the same signal data. The simple, reliable and low-cost method is provided for system identification on industrial site.

Description

technical field [0001] The invention relates to a system identification method based on a host computer and a programmable controller. Background technique [0002] The upper computer WinCC+lower computer programmable logic controller (PLC) is the main form of the industrial site monitoring system. PLC is mostly used to realize switching control, analog input and output, and logic operation functions, but it is rarely used for system identification research. On the one hand, because the excitation signal used for system identification is very demanding, it must have rich changes, and can continuously stimulate all modes of the identification process, which is not easy to achieve by using a programmable controller to generate an excitation signal; on the other hand, to carry out During system identification, the input and output data must be collected at high speed in order to obtain a large amount of rich data. However, the minimum refresh period of WinCC is only 250ms, an...

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Problems solved by technology

However, the minimum refresh period of WinCC is only 250ms, and the minimum data archiving period is 500ms, which is far greater than the sampling period of PLC. If it is not developed, it will not be possible to achieve high-speed data collection and storage

At present, in the experimental research of system identification, high-speed acquisition modules such as data acquisition cards and DSP are mostly used, and they are used in conjunction with LABVIEW and other host computer software that are convenient for generating excitation signals, but this undoubtedly increases the hardware cost, and cannot be compared with the original control The system achieves a good integration

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